Device for producing anastomoses and coagulation electrode

ABSTRACT

A device for producing anastomoses between first and a second hollow organs, each having inner and outer surfaces. The device comprises a sleeve with an electrode arrangement, over which the first hollow organ is placed such that its inner surface comes to lie on a outermost surface of the sleeve, and an outer electrode arrangement, which can be brought into electrical contact with the opposing electrode arrangement carrying the second hollow organ, which is pushed over the first hollow organ. The outer electrode arrangement comprises a plurality of lamellae, configured and arranged such that, in a closed state, the lamellae form a through aperture and the inner edges of the lamellae lie against the second hollow organ and, in an open state, a gap is formed between the lamellae, through which the hollow organs connected to one another can be guided outwardly out of the through aperture.

The invention relates to a device for producing anastomoses according tothe preamble of claim 1 and a coagulation electrode according to claim11.

An anastomosis is a connection between two anatomical structures. Forexample, blood vessels severed during an organ transplantation can beconnected to one another by means of anastomoses.

In surgery, various methods for producing such anastomoses are known.For example, the connection can be made using suturing techniques.Inserts also exist which permit organic connection by means of adhesivetechniques. In this context, fibrin glues are often used, and theseenable very advantageous connection of organs, particularly holloworgans. However, the tolerability of such adhesives is problematic,since they can have thrombogenic and toxic properties.

Clamping techniques are also used to create a connection at a suitablesite. In order to assist the production of anastomoses, various aids,such as rings, cuffs or stents are used.

It is herein disadvantageous that these aids usually remain in thehollow organ being connected and can cause rejection reactions there orincrease the risk of thromboses.

WO 03/061487 A1 discloses connecting hollow organs by the application ofa suitable high frequency (HF) current. When the HF current is applied,biological welding of the tissue structures takes place. The cellularsubstance coagulates with the result that the protein structures adhere,so that a controlled, secure and rapid connection can be created. WO03/061487 A1 provides an instrument for the application of an HFcurrent, said instrument comprising an inner sleeve and an outer sleeve.These sleeves each comprise an electrode which is formed ring-shaped andto which the HF current is supplied. This instrument is a bipolar HFinstrument. In order to connect the ends of a blood vessel, the firstend is guided through the inner sleeve and is folded over such that thetissue comes to lie against the outside of the inner sleeve. The secondend of the vessel is pulled over the inner sleeve and the end section ofthe blood vessel situated thereon. The outer sleeve can be opened andplaced over the inner sleeve and the tissue situated thereon. Theelectrodes are arranged on the sleeves such that the first and secondends of the vessel are damped between the electrodes on the sleeves. Onapplication of the HF current, said current flows through the tissue andwelds the ends.

A problem with WO 03/061487 A1 lies in the fact that in order to weld orcoagulate hollow organs having different diameters, a plurality ofdifferently configured instruments is needed. In particular, the gapbetween the electrodes and the sleeves must be dimensioned so that it ismatched to the thicknesses of the walls.

Only when the electrodes are optimally placed on the tissue structuresdoes advantageous welding of the tissue structures take place. Thecoagulation procedure requires continuous pressure on the tissuestructures or vessel end sections throughout the coagulation process.

The results finally achieved with the instrument disclosed in WO03/061487 A1 are strongly dependent on the choice of a suitableinstrument, i.e. on the judgment of the treating physician and aretherefore difficult to document and reproduce.

Proceeding from this prior art, it is an object of the present inventionto provide a device for producing anastomoses between a first and asecond hollow organ, which is simple to operate and is suitable forforming high quality anastomoses, whilst also avoiding theaforementioned disadvantages. A coagulation electrode suitable for thispurpose is also to be provided.

The present invention solves this problem with the device according toclaim 1 and the coagulation electrode according to claim 11.

In particular, the problem is solved with a device for producinganastomoses between a first and a second hollow organ, each having aninner surface and an outer surface, said device comprising a sleeve withan inner electrode arrangement, over which the first hollow organ isplaced such that the inner surface thereof comes to lie outermost, andan outer electrode arrangement which is situated, in particular,radially opposing the inner electrode arrangement and can be broughtinto electrical contact with the second hollow organ, which is pushedover the first hollow organ, such that the electrode arrangements makecontact with the outer surfaces of the hollow organs, wherein the outerelectrode arrangement comprises a plurality of lamellae which aremovable relative to one another by means of at least one guide memberand which are configured and arranged movable such that, in a closedstate, inner edges of the lamellae form a through aperture and lieagainst the second hollow organ and, in an open state, a gap is formedbetween the lamellae, leading from outside to the through aperture,through which the hollow organs connected to one another can be guidedoutwardly out of the through aperture.

An essential concept of the present invention therefore lies thereinthat the outer electrode is formed by a plurality of lamellae which aremovable relative to one another. The lamellae are arranged such thatthey are able to assume at least two states, specifically a closed stateand an open state. In the open state, at least the lamellae are spacedapart from the sleeve with the inner electrode arrangement such that athrough aperture is formed, in which the relevant sections of the holloworgans can be positioned, preferably largely in the absence of tissuecontact or radial force application. In the closed state, the inneredges of the lamellae lie at least partially on the hollow organ andenable direct application of the HF current. The outer electrodearrangement with the lamellae is partable. In the open state, a gap canform, dividing the lamellae. Due to the gap, the unconnected holloworgan or vessel can be introduced and the connected organ or vessel canbe removed from the device.

Preferably, the lamellae can exert mechanical pressure on the holloworgans. The closing and coagulation conditions can be determinedrelatively precisely. By this means, the formation of anastomoses havinga high load-bearing capability can be ensured. Following connection ofthe hollow organs, the device can be easily removed in the open state.Injury to the organs or excessive loading of the connection created isavoided.

The lamellae can be adjustable such that, in the closed state, anaperture is formed which matches the hollow organ to be treated. Holloworgans with different dimensions can therefore be treated with a deviceaccording to the present invention. For example, blood vessels withdifferent diameters can be treated. An instrument can be suitable forconnecting veins and arteries.

The lamellae can be constructed and/or arranged in the manner of an irisdiaphragm. The through aperture is therefore formed substantiallycircular. This is advantageous for a number of applications, such as theconnection of vessels. Furthermore, an iris diaphragm is particularlysuitable for providing an essentially continuous contact surface of thelamellae. A continuous application of the HF current therefore takesplace. An applied mechanical pressure can be evenly distributed over theouter surface and surfaces of the second hollow organ.

The sleeve can be arranged fixed relative to the outer electrode in aholder or mounting. The sleeve is then arranged in a predeterminedposition relative to the outer electrode. Positioning of the sleeverelative to the outer electrode is therefore dispensable. In addition,the device according to the invention can be constructed substantiallymore compact by fixing in a holder. Handling is simplified by the fixedor adjustable positioning.

The mounting can be removed for individual manipulation of the sleeve.This means that the mounting can be released from the device and usedseparately therefrom. It is therefore possible, in a preparation phase,to arrange the first hollow organ and/or the second hollow organ in oron the sleeve. Then, the sleeve and the device can be coupled such thatthe sleeve is situated in an advantageous position relative to the outerelectrodes. Following the coagulation procedure, it can be advantageousto release the mounting from the device again, in order not to strainthe connected hollow organs unnecessarily.

In the closed state, the inner edges of the lamellae can be spaced atsubstantially the same distance from the sleeve. Therefore, in theclosed state, the inner edges lie against the second hollow organ,particularly on the inner surface thereof. The HF current is applieddirectly to the tissue. The connection achieved is of correspondinglybetter quality.

The diameter of the through aperture is adjustable with the movement ofthe lamellae. The device can therefore be opened and closed by movingthe lamellae.

In the open state, the gap can divide the outer electrode in two halves,which are movable apart from one another. It is thus possible to createan iris, which can be divided, for example, into two semicircles. Thisfacilitates the safe removal of the device following a coagulationprocedure.

The sleeve can be held on an actuating device and can be configured ableto be dismantled into two parts such that the parts can also be broughtfrom a closed state forming a closed tubular section, into an open statefor removal from the hollow organ. The sleeve can therefore beconfigured in two parts, so that said sleeve can be disassembled afteror before the application of the HF current. For example, it may bepossible to spread the individual parts of the sleeve apart in order toensure better handling of the organs. The spreading of the sleeve canalso prevent the hollow organ placed over the sleeve from slipping off.

In a closed state, the actuating device can be pre-tensioned. The closedstate therefore establishes itself automatically.

The lamellae can be pre-tensioned into the closed state with a definedforce by a tensioning device. Preferably, the pre-tensioning device canbe adjusted so that, in the closed state, the lamellae are pressed witha pre-defined force against the hollow organs. This force not onlyenables reliable coagulation of the tissue, but is also dimensioned sothat the hollow organs are not damaged. By setting the tensioningdevice, repeatability of the treatment results can be assured.

The problem defined above is also solved with a coagulation electrode,comprising:

-   -   a mounting ring;    -   a plurality of lamellae mounted on the mounting ring, said        lamellae being pivotable from an open state to a closed state in        the manner of an iris diaphragm, in order to form electrode        sections;    -   a linkage ring which is arranged rotatable relative to the        mounting ring and engages with guide members on the lamellae        such that on rotation of the linkage ring relative to the        mounting ring, the lamellae are pivoted from the closed state        into the open state and vice versa, wherein the mounting ring        and the linkage ring are each configured in two parts such that        they can be moved away from one another together with the        lamellae mounted on the mounting ring and engaging with the        linkage ring.

A coagulation electrode of this type has similar advantages to theaforementioned device. In particular, the coagulation electrode ispartable and is therefore easily removed after application of the HFcurrent. This means that the coagulation electrode can easily be removedfrom the connected hollow organ.

The linkage ring can also can also be a lamella and assume the functionthereof.

The linkage ring can comprise linkage ring sections which are movableseparately from one another, in particular, with guide rods.

The linkage ring can comprise exactly two linkage ring sections formingthe linkage ring. The sections can serve to actuate the lamellae. Inparticular, the lamellae can be rotated relative to the mounting ring(preferably comprising two mounting ring sections). The lamellae arebrought into the open or closed state.

The invention will now be described in greater detail using someexemplary embodiments, illustrated by the drawings, in which:

FIG. 1 shows an electrosurgical instrument for producing anastomoses,with the arms opened;

FIG. 2 shows the instrument of FIG. 1 with the arms closed (and irisdiaphragm open);

FIG. 3 shows the instrument of FIGS. 1 and 2 with the arms closed (andthe iris diaphragm closed),

FIG. 4 shows a closing force adjusting device for the instrument ofFIGS. 1 to 3;

FIG. 5 shows a detailed view of a section of the iris diaphragm of FIG.1 with a positioning device;

FIG. 6 shows the iris diaphragm of FIG. 5 in an exploded view;

FIG. 7 shows a further embodiment of the lamellae for an iris diaphragm;

FIG. 8 shows a detailed view of the iris diaphragm of FIG. 1 (irisdiaphragm closed);

FIG. 9 shows a detailed view of the iris diaphragm of FIG. 1 (irisdiaphragm open);

FIG. 10 shows a detailed view of a further embodiment of an irisdiaphragm (iris diaphragm closed);

FIG. 11 shows the iris diaphragm of FIG. 10 (iris diaphragm open);

FIG. 12 shows a further embodiment of the iris diaphragm in an explodedview;

FIGS. 13 and 14 show detailed views of the iris diaphragm of FIG. 12.

In the following description, the same reference signs are used forsimilar and similarly acting parts.

FIG. 1 shows an electrosurgical instrument 10 for producing anastomoses.The instrument 10 comprises a base plate 13, on which arms 12, 12′ arepivotably mounted. A closing device 20 serves to actuate the arms 12,12′. Said closing device comprises a closure actuating element 24 whichis connected via a linkage guide to the arms 12, 12′. The closureactuating element 24 has essentially two positions, specifically a firstposition in which the electrosurgical instrument 10 is open and a secondposition in which the electrosurgical instrument 10 is closed.Preferably, the closing device 20 is configured so that the arms 12, 12′are fixed in the second position such that unintentional opening of theelectrosurgical instrument 10 is not possible (see FIG. 2).

Situated at the distal end of the arms 12, 12′ are half diaphragms 51,51′, which form an iris diaphragm 50 in the closed state of theelectrosurgical instrument 10 (see FIGS. 2 and 3).

The electrosurgical instrument 10 also has a tensioning device 40 foractuating the iris diaphragm 50. Said tensioning device 40 comprises atensioning device actuating element 42 and a force deflector 44 whichare pivotably mounted on the base plate 13, a tensioning spring 41 andtwo actuating elements 52, 52′. The actuating elements 52, 52′ extend,respectively, along the first arm 12 and the second arm 12′ and transmitthe forces exerted by the tensioning device 40 to the mechanism of theiris diaphragm 50. In the open position of the electrosurgicalinstrument 10, the tensioning device 40 is also in an open position (seeFIG. 1). In the second, closed position of the electrosurgicalinstrument 10, the tensioning device 40 can be tensioned by actuatingthe tensioning device actuating element 42. FIG. 3 shows the tensioningdevice actuating element 42 in the tensioned state. On actuation of thetensioning device actuating element 42, the tensioning spring 41 whichis connected to the force deflector 44 is tensioned. This results in arotary movement of the force deflector 44 about a pivot point situatedbetween the arms 12, 12′. The rods or actuating elements 52, 52′ whichare attached to the force deflector 44 essentially symmetrically aboutsaid pivot point execute a translation movement in the proximal(actuating element 52′) or the distal (actuating element 52) direction.This movement leads, as described in greater detail below, to closingand opening of the iris diaphragm 50.

It should be noted that, in the tensioned state, the tensioning spring41 continuously exerts a force, via the actuating elements 52, 52′ onthe mechanism of the iris diaphragm 50. The value of this force can beadjusted with a closing force adjusting device 45 (see FIG. 3). Theembodiment of the force deflector 44 as shown in FIG. 3 comprises aplurality of bores with different distances from the pivot point of theforce deflector 44. The tensioning spring 41 is configured such thatsaid spring can be anchored in the individual bores. The spring force ofthe tensioning spring 41 is therefore applied to the force deflector 44with a different leverage depending on the position in the bores. Asshown in FIGS. 1-3, the force deflector 44 extends beyond the base plate15 such that said force deflector is manually actuatable. The irisdiaphragm 50 can also be opened and closed in the non-tensioned statevia the force deflector 44, which serves as an actuating element.

FIG. 4 shows a further embodiment of the tensioning device 40. In thiscase, the closing force adjusting device 45 comprises an adjusting screw46 and an angle bracket 47. The angle bracket 47 is fastened to theforce deflector 44 such that said angle bracket can be displaced along alongitudinal axis by actuation of the adjusting screw 46. In theexemplary embodiment shown in FIG. 4, the tensioning spring 41 acts onthe angle bracket 47. By actuating the adjusting screw 46, the leverwith which the tensioning spring 41 exerts the force on the forcedeflector 44 can be steplessly adjusted.

A further essential element of the electrosurgical instrument 10 is apositioning device 30 (see FIG. 5). Said positioning device comprises asleeve 32 for accommodating the hollow organs and two sleeve actuatingarms 35, 35′. The positioning device 30 essentially serves to positionthe hollow organs in the centre of the iris diaphragm 50. It alsoprovides a sleeve electrode 36. The sleeve 32 is constructed essentiallycylindrically and comprises a first sleeve section 33 and a secondsleeve section 33′. In cross-section, transversely to the longitudinalaxis of the sleeve 32, the sleeve sections 33, 33′ each form asemicircle. The sleeve sections 33, 33′ are connected to the sleeveactuating arms 35 and 35′, respectively. Said actuating arms arepivotably fastened to a removable section 13′ of the base plate 13, suchthat the sleeve sections 33, 33′ can be opened and closed. In the closedstate, the sleeve sections 33, 33′ lie against one another and form thesleeve 32. The positioning device 30 can thus be opened and closed viathe sleeve actuating arms 35, 35′. Preferably, a spring force whichkeeps the sleeve sections 33, 33′ closed is applied to the sleeveactuating arms 35, 35′. The removable section 13′ on which the sleeveactuating arms 35, 35′ are pivotably mounted is connected to the baseplate 13 via a plug-in connection. In order to accommodate the holloworgans, the positioning device 30 can be detached from the remainingcomponents of the electrosurgical instrument 10 and individuallyoperated.

The partability of the sleeve 32 is particularly advantageous whenplacing the instrument 10 on, and removing the instrument from, thehollow organ. In order further to facilitate this procedure, the sleeve32 comprises at least two spikes 28 which are arranged on the sleevesections 33, 33′, radially to the longitudinal axis of the sleeve 32. Ifthe hollow organ or the sections thereof is pushed over the sleeve 32,the spikes 28 fix the hollow organs or vessels that have been placedthereon. The sleeve actuating arms 35, 35′ limit the advance of saidorgans.

Following accommodation of the hollow organs, the removable section 13′can be reconnected to the base plate 13 and brought into a positionwhich is suitable for connecting the sections of the hollow organ.

An essential point of the present invention lies in constructing thedevice head of the electrosurgical instrument 10 in the form of apartable iris diaphragm. As shown in FIG. 1, the iris diaphragm 50comprises two half diaphragms 51, 51′ which, in the closed state,cooperate as one iris diaphragm 50. The construction of a halfdiaphragm, specifically the half diaphragm 51 is illustrated in FIG. 6.Said half diaphragm comprises a fastening plate 56 which is configuredessentially semicircular and is firmly connected to the first arm 12. Analso semicircular shell 57 extends along the outer edge of saidfastening plate 56. The shell 57 has an aperture 60 through which asickle-shaped actuating plate 54 extends into the interior of the halfdiaphragm 51. The actuating plate 54 can be actuated by means of theactuating element 52 such that said actuating plate performs a circularmovement about the center of the iris diaphragm 50. Arranged between theactuating plate 54 and the fastening plate 56 is a plurality of lamellae53, 53′, 53″, which are partially pivotably connected to the fasteningplate 56. Claws 59, 59′ on the lamellae 53, 53′, 53″ engage incorresponding lamellar linkage plates 58 in the actuating plate 54. Thelamellae 53, 53′, 53″ are configured and arranged such that theorientation of the lamellae 53, 53′, 53″ can be altered by the movementof the actuating plate 54. As FIGS. 8 and 9 show, the lamellae canassume at least two positions. The lamellae 53, 53′, 53″ have innerwalls 66 which act as electrodes. In a first position (FIG. 9), thelamellae 53, 53′ are positioned so as to hardly project beyond theactuating plate 54. A circular through aperture forms, into which thesleeve 32 extends. Situated between the sleeve 32 and the inner edges 66of the lamellae 53, 53′ is a gap which is suitable for accommodatingsections of the hollow organs.

In a closed position, the through aperture is reduced such that theinner edges 66 of the lamellae 53, 53′, 53″ lie against the sleeve 32(see FIG. 8). Insofar as tissue sections of the hollow organs aresituated between the inner edges of the lamellae 53, 53′, 53″ and thesleeve 32, they are pressed against one another and against the sleeve32 with a defined force. This force can be adjusted with the closingforce adjusting device 45 and is transferred via the actuating elements52, 52′ to the lamellae 53, 53′, 53″.

The covers 55, 55 a are alternately placed on the half diaphragms 51,51′ and protect their mechanisms.

FIG. 7 shows a further embodiment of the lamellae 53, 53′. Said lamellaeare configured stepped and close in such a manner that a first lamella53 not only slides over the second lamella 53′, but also engagestherein.

A further embodiment of the lamellae 53, 53′ is shown in FIGS. 10 and11. FIGS. 10 and 11 show the iris diaphragm 50 according to theinvention in a plan view, wherein the iris diaphragm 50 is closed inFIG. 10 and is open in FIG. 11. For the sake of a better view of themechanism of the iris diaphragm 50, the cover 55′ is removed in FIG. 10.It is apparent that the lamellae 53, 53′ engage via T-anchors 59 a, 59a′ in the lamellar linkage plate 58 of the actuating plate 54. TheT-anchors 59 a, 59 a′ assume the function of the claws 59, 59′. Pinswhich are arranged on the actuating plate 54 of the half diaphragms 51,51′ and engage in the covers 55, 55′, form a linkage guide for theactuating plates 54. Said pins guide the actuating plates 54, during therotation movement thereof, about the center of the iris diaphragm 50 andthus increase the closing range of the lamellae.

FIGS. 12 to 14 show a further exemplary embodiment of the mechanism ofthe iris diaphragm 50 according to the invention having a simplerconstruction. In order to explain the mechanical processes, a coordinatesystem will now be introduced. The X-axis of this coordinate systemextends essentially along one arm 12. The Y-axis lies transverselythereto and points toward the centre of the through aperture of the irisdiaphragm 50.

FIG. 12 shows, by way of example, the first half diaphragm 51 in anexploded view. A substantial difference in the exemplary embodimentaccording to FIGS. 12 to 14 as compared with FIG. 6 lies therein thatthe function of the actuating plate 54 in the exemplary embodiments ofFIGS. 12 to 14 is realized by a lamella 53 to 53″, specifically thelamella 53′. The fastening plate 56 of FIG. 12 is also firmly connectedto the first arm 12. Said fastening plate has three cut-outs 61, 61′,61″, which open radially in the direction of the centre of the throughaperture of the iris diaphragm 50. Lamella pins 63, 63′, 63″ are placedin said cut-outs 61, 61′, 61″. Said pins are arranged essentiallycentrally on the lamellae 53, 53′, 53″. The cut-outs 61, 61′, 61″ form alinkage guide along which the individual lamellae 53, 53′, 53″ can bemoved toward the center of the through aperture. The lamella pins 63,63′, 63″ are provided on both sides of the lamellae 53, 53′, 53″. Theyengage, on one side, in the cut-outs 61, 61′, 61″ of the fastening plate56 and, on the other side of the lamellae 53, 53′, 53″, in cut-outs 65,65′, 65″ of the cover 55. The cut-outs 65, 65′, 65″ of the covers 55also extend essentially toward the center of the through aperture of theiris diaphragm 50. The lamella 53′ is rigidly connected to the actuatingelement 52 and has a corresponding projection for this purpose. Theactuating element 52 is actuated along the Y-axis. Therefore, by meansof the actuating element 52, the second lamella 53′ can be moved in thedirection toward the center of the through aperture. The semicircularlamellae 53 to 53″ each have a cut-out 64, 64′, 64″, 64′″ at their ends,which engage with the pins 63, 63′, 63″ of the other lamellae 53 to 53″.A mechanical coupling is therefore made between the first lamella 53 andthe second lamella 53′ (cut-outs 64, 64′) which, in turn, is connectedto the third lamella 53″ (cut-outs 64″, 64′″). The movement of thesecond lamella 53′ along the Y-axis causes actuation and displacement ofthe first and third lamellae 53, 53″. The linkage guides are configuredin order to move each of the lamellae 53 to 53″ toward the center of thethrough aperture when the second lamella 53′ is displaced along theY-axis. A contrary movement of the second lamella 53′ causes thismovement to be reversed. The iris diaphragm 50 opens.

The second half diaphragm is correspondingly symmetrically constructed.FIGS. 13 and 14 show the half diaphragms 51, 51′. It is apparent that,in a closed state of the electrosurgical instrument 10, the firstlamella 53 of the first half diaphragm 51 enters into a mechanicalconnection with the lamella 53″″ lying opposed thereto. Here also, thereis a connection between the lamella pins 63, 63′, 63″ and the cut-outs64, 64′, 64″. The same applies for the third lamella 53″.

The coupling of the lamellae 53 to 53″ of the first half diaphragm 51 tothe lamellae of the second half diaphragm 51 is releasable. In theopened state of the instrument 10, the iris diaphragm 50 has a gap, bymeans of which the connected hollow organ can be separated from theinstrument 10. Therefore, in the closed state of the electrosurgicalinstrument 10, a ring of lamellae 53 to 53″″ is formed, comprising sixlamellae according to the exemplary embodiment of FIGS. 12 to 14. Theindividual lamellae 53-53″′ are each in operative connection with theadjacent lamellae 53-53″′. Taken altogether, a linkage guide is formedwhich enables a translation movement of the individual lamellae 53 to53′″ in the direction toward the center of the through aperture.Actuation of the actuating elements 52, 52′″ is therefore transferredmechanically to the individual lamellae 53 to 53″'.

According to the invention, the iris diaphragm 50 comprises a firstouter electrode arrangement or outer electrode and the sleeve 32comprises an inner electrode arrangement, specifically the sleeveelectrode 36. As FIG. 5 shows, these electrodes are arranged adjoiningone another. The sections of hollow organs clamped between the irisdiaphragm 50 and the sleeve 32 can be connected to one another by meansof these electrodes. For this purpose, a corresponding HF current isapplied to the electrodes. The HF current causes coagulation of thetissue sections situated between the electrodes. In order to apply theHF current, the electrosurgical instrument 10 has suitable conductortracks and terminals. For example, the sleeve electrode 36 can besupplied via a conductor track within the sleeve actuating arms 55, 55′.A suitable conductor track for the iris diaphragm can be situated withinthe arms 12, 12′.

Alternatively, the arms 12, 12′ and/or the sleeve actuating arms 53, 53′can be entirely or partially constructed from electrically conductivematerial in order to provide a suitable conductor track.

The individual lamellae 53 to 53′″ can comprise electrodes for applyingthe HF current and/or can be made from electrically conductive material.

Preferably, the base plate 13 and the removable section 13′ of the baseplate 13 is an electrical insulator. Thus the conductor track of thesleeve electrode 36 is electrically insulated from at least theconductor track of the iris diaphragm 50.

In a further exemplary embodiment, the base plate 13 and/or theremovable section 13′ can comprise terminals and electrical conductortracks in order to supply the electrodes.

Exemplary embodiments with four and eight lamellae 53 to 53″″ have beendescribed. Other embodiments with other numbers of lamellae 53 to 53″″are also conceivable (e.g. with at least four lamellae 53 to 53″″).

REFERENCE SIGNS

-   10 Electrosurgical instrument-   12, 12′ Arms-   13 Base plate-   13′ Removable section of the base plate-   20 Closing device-   24 Closure actuating element-   28 Spike or fixing element-   30 Positioning device-   32 Sleeve-   33, 33′ Sleeve section-   35, 35″ Sleeve actuating arm-   36 Sleeve electrode-   40 Tensioning device-   41 Tensioning spring-   42 Tensioning device actuating element-   44 Force deflector-   45 Closing force adjusting device-   46 Adjusting screw-   47 Angle bracket-   50 Iris diaphragm-   51, 51′ Half diaphragm-   52, 52′ Actuating element-   53 to 53″′ Lamella-   54 Actuating plate-   55, 55′, 55 a Cover-   56 Fastening plate-   57 Shell-   58 Lamellar linkage plate in the actuating plate-   59, 59′ Claw-   59 a, 59 a′ T-anchor-   60 Aperture-   61, 61′, 61″ Cut-out in the fastening plate-   63, 63′, 63″ Lamella pin-   64, 64′, 64″ Cut-out in the lamella-   65, 65′, 65″ Cut-out in the cover-   66 Inner edge

1-12. (canceled)
 13. A coagulation electrode, comprising: a mountingring; a plurality of lamellae mounted on the mounting ring, saidlamellae being pivotable from an open state to a closed state, in themanner of an iris diaphragm, to form electrode sections; a linkage ring,which is arranged rotatable relative to the mounting ring and engageswith guide members on the lamellae such that, on rotation of the linkagering relative to the mounting ring, the lamellae are pivoted from theclosed state into the open state and vice versa, wherein the mountingring and the linkage ring are each configured in two parts such thatthey can be moved away from one another together with the lamellaemounted on the mounting ring and engaging with the linkage ring.
 14. Thecoagulation electrode of claim 13, wherein the linkage ring is dividedinto two parts, such that said ring comprises first and second linkagering sections that are movable separately from one another.
 15. Thecoagulation electrode of claim 14, wherein the first and second linkagering sections are movable by guide rods.